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geoDefense Swarm is an open-space, maze-based followup to the original geoDefense, a hardcore tower defense game that sparked a “love it or hate it” relationship. If you enjoyed that game, you’ll love this one, and if you didn’t, well, Swarm won’t do anything to change your mind.

Like its predecessor, this game doesn’t pull any punches. The creeps here are relentless, and they’ll rush you at an incredible speed. There’s very little time to build your own maze in the beginning of the level, so expect to restart a few times before you figure out a decent defensive strategy.

Crafting a defensive strategy can be very difficult at first, as the game doesn’t do a very good job of explaining how to play. A few tips pop up on the first couple of levels, but none actually go so far to tell you what the differences are between towers.

For some reason I feel like Honeycomb Cereal…

This will leave you wondering just what, exactly, a thump tower does (it sends out damage 360 degrees, but does so little it’s hard to tell if anything is happening until it’s been upgraded). You also may have trouble understanding why your missile towers seem to miss half the time (they too, need to be upgraded) and why your laser towers don’t efficiently target enemies (ditto).

These intricacies are appreciated, but really shouldn’t be left for the player to discover. As we said before, this is a brutal game that moves at a very quick pace. It’s extremely difficult to notice these things while frantically planning a maze, constructing towers, upgrading existing towers and battling dozens of enemies at the same time.

Once you do understand how to play, expect to have a good time. Crafting your own maze gives you plenty of options for taking out the creeps, so there’s more than one way to beat each level. The levels themselves can get pretty creative, and force you to work around some obstacles. Sometimes you won’t be able to build in a certain spot on the grid, and other spots will heal creeps or make them move faster.

This game gets intense.

There are a total of 30 levels split into three levels of difficulty. The easy levels are still pretty challenging, and the hard levels may spur you to chuck your iPhone through the wall. All the levels end after a set number of waves, except for the final stage of each difficulty level, which go on endlessly until you die. Online leaderboards are supported through OpenFeint, a thoughtful addition.

Graphically, the game is solid, adopting the fireworks filled style of the Geometry Wars games. Everything here looks very similar to the original geoDefense game. Our only complaint is that it’s often hard to distinguish which towers you’ve upgraded and which you haven’t.

Really, despite the initial difficulty, the actual game here is pretty rock solid. If you’re a fan of tower defense games or consider yourself worthy of any challenge, we highly recommend you pick this up. If you’re easily frustrated or need quite a bit of guidance in your games, this isn’t for you.

On a system choked with tower defense games, the original geoDefense stood out as one of the most unhinged, twitch-responsive, action-packed instances of the genre we’ve played. Since its release, developer Critical Thought Games has been hard at work on the followup, geoDefense Swarm. Can this new iteration duplicate the energy and success of the original? We got our mitts on a near-final build of the game to find out.

The original geoDefense was a tower defense game defined by the linear paths the critters traversed to get to the exit. The only variables you had to worry about were the creeps’ toughness and speed. geoDefense Swarm is a different beast altogether. It eschews the path mechanic for an open-space level design, and also adds a few other twists while still maintaining the key elements of the original.

Now that you have to worry about what route the critters will take, a new layer of strategy is required on the part of the player. Left to their own devices, the creeps will find the shortest path and bee-line to the exit as quickly as possible. So, as with most open-space tower defense games, you’ll want to carefully place your towers to create a gauntlet for the baddies to run through. And just like in the original geoDefense, the creeps come in ever-stronger waves.

Each map is laid out on a hexagon-based honeycomb grid. Every stage has a uinique shape and is composed of different types of terrain. Some hexes the creeps can’t traverse, some you can’t build towers on, and some have special attributes, like speeding the creeps up or healing them. Much of your strategy is dependent on the terrain, but you don’t have much time to plan your defense before the creeps start their invasion. Take it from us: you’ll have to replay levels often, honing your strategy each time.

Once again you’ll find three levels of difficulty, with ten unique stages in each. According to developer David Whatley, an endless mode was the most requested feature by fans of the original game. To that end, the final map of each difficulty level is now host to an endless swarm mode, where the creeps keep on coming as long as you can fend them off.

One new tower type has been added this time around: the Thump Tower. It emanates shockwaves that damage any creeps within range. The other towers are still available, although Vortex Towers are now pre-placed within certain stages and cannot be moved. There are six towers total, each of which can be upgraded seven times.

All the critters from the original are back, along with a new one that looks like a swarm of sparks. These new creeps are actually healed by laser fire, so you’ll have to plan accordingly. Online leaderboards, tracked by OpenFeint, have been included as well. geoDefense Swarm will cost $0.99 at launch, and Critical Thought Games is hoping for a release date of August 14.

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